DropBox is an innovative file synchronization service that seamlessly keeps the assigned folder between computers in sync. You can even get to your files from anywhere via a browser interface.
Dropbox team just announced today that they are releasing a iPhone App shortly.
The great thing about Dropbox is that you install a client on your machines and just forget about. It seamlessly integrates in the native file explorer and syncs in the background. It is intelligent enough to sync the most recent files first (matters when you are syncing a new computer). Also, it keeps different revisions of a file as you change it from various computers. So this is great for collaboration as well.
Dropbox app on iPhone (coming soon!):
Visit Dropbox to register, download and install. Its free 😉